WASHINGTON — The Republican head of a Senate panel warned U.S. nuclear regulators on Thursday that he would introduce legislation if they fail to shore up oversight gaps that led to severe corrosion at an Ohio nuclear plant.

Congress’ investigative arm, the General Accounting Office, earlier this week criticized the Nuclear Regulatory Commission for failing to act quickly after spotting leaking boric acid that nearly chewed through the reactor at the plant owned by FirstEnergy Corp.

Ohio Sen. George Voinovich, head of a Senate subcommittee on nuclear safety, asked NRC Chairman Nils Diaz to explain why the agency didn’t do more to address safety standards at the 103 U.S. commercial nuclear plants it regulates.

Agency: 'Unaccceptable failure'Diaz called the incident at the Davis-Besse plant an ”unacceptable failure” by the NRC and FirstEnergy. But imposing specific “safety culture” rules is the responsibility of plant owners, not the NRC, Diaz said.

“We do not believe that’s the role of the commission,” Diaz said at a hearing of the Senate subcommittee. FirstEnergy “did not meet its own definition of safety culture,” Diaz said.

Voinovich rebuked Diaz by saying that “if you won’t do it, I’ll get legislation passed to get it done.”

The General Accounting Office study found the NRC “should have, but did not, identify or prevent the corrosion at Davis-Besse because its oversight did not generate accurate information on plant conditions.” Other problems could occur because the NRC hasn’t done enough to monitor safety, it said.

Leaking boric acid, used as a coolant, ate a cantaloupe-sized hole in the outer hull of the reactor in Oak Harbor, Ohio, about 35 miles east of Toledo. The leaking boric acid had eaten almost through a 6-inch-thick steel cap.

No radiation was released into the air, but it was a serious safety violation. The NRC ordered the plant shut in early 2002.

FirstEnergy returned the plant to full power last month after it spent $600 million to repair the damage.

'Adequate assurances' lacking
Davis-Besse was among 14 plants that were supposed to have been inspected in the fall of 2001 because of cracking in nozzles on the reactor head. The NRC, however, allowed the plant to postpone the inspection until a scheduled maintenance shutdown months later.

Had the commission shut down the plant sooner, officials would have found a corroded hole that nearly penetrated the reactor, the GAO said. The auditors said that three years later, they still aren’t convinced that the NRC has addressed the problem adequately.

“We do not yet have adequate assurances from NRC that many of the factors that contributed to the incident at Davis-Besse will be fully addressed,” said the GAO report.

The GAO said that three engineering consultants it retained concluded that the reasons cited by the NRC for delaying the shutdown in 2001 “lacked credibility.” It said the decision was so poorly documented that they couldn’t judge if it was reasonable.

The commission was faulted by the auditors for not making plant owners cultivate a “safety culture” among reactor workers and managers. The NRC should have better guidelines on when to shut down reactors for safety concerns, the auditors said.

NRC spokesman Scott Burnell said Tuesday the agency has such guidelines. “There are many areas of oversight, regulations, the technical specifications that a plant has to follow while it shuts down in order to be in compliance with its license,” he said.

Burnell said the idea of assessing a plant’s safety culture “is too subjective to have any real effect on safety performance.”

The commission’s executive director, William Travers, said the GAO auditors did not take into account how much the agency depends on reactor operators to tell the truth about plant conditions.

The NRC contends FirstEnergy gave the agency inaccurate and incomplete information about the reactor lid’s status. A federal grand jury is probing whether the utility did so intentionally.